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A229426 Number of n X 6 0..2 arrays with horizontal differences mod 3 never 1, vertical differences mod 3 never -1, rows lexicographically nondecreasing, and columns lexicographically nonincreasing.

%I A229426 #6 May 21 2023 21:46:40
%S A229426 23,175,1116,5700,24126,87648,281016,812352,2152643,5297329,12231874,
%T A229426 26724490,55625600,110928984,212948248,395089316,710860767,1243965435,
%U A229426 2122565928,3539121568,5777563514,9250018192,14545817232,22496156480
%N A229426 Number of n X 6 0..2 arrays with horizontal differences mod 3 never 1, vertical differences mod 3 never -1, rows lexicographically nondecreasing, and columns lexicographically nonincreasing.
%C A229426 Column 6 of A229428.
%H A229426 R. H. Hardin, <a href="/A229426/b229426.txt">Table of n, a(n) for n = 1..210</a>
%F A229426 Empirical: a(n) = (1/11404800)*n^12 + (1/211200)*n^11 + (37/345600)*n^10 + (143/103680)*n^9 + (27977/2419200)*n^8 + (83399/1209600)*n^7 + (321133/1036800)*n^6 + (35291/34560)*n^5 + (66941/28800)*n^4 + (614843/129600)*n^3 + (149511/30800)*n^2 + (19627/3465)*n + 4.
%e A229426 Some solutions for n=4
%e A229426 ..2..2..1..0..0..0....1..0..0..0..0..0....2..2..1..1..1..0....2..2..2..1..1..1
%e A229426 ..2..2..1..1..1..0....2..1..0..0..0..0....2..2..1..1..1..0....2..2..2..1..1..1
%e A229426 ..2..2..1..1..1..0....2..1..0..0..0..0....2..2..2..1..1..0....2..2..2..1..1..1
%e A229426 ..2..2..2..1..1..0....2..2..1..1..0..0....2..2..2..1..1..0....2..2..2..2..1..1
%Y A229426 Cf. A229428.
%K A229426 nonn
%O A229426 1,1
%A A229426 _R. H. Hardin_, Sep 22 2013